Tag Archives: ar 15 carbine bolt upgrade

By David Crane defrev (at) gmail (dot) com November 10, 2009 Back in April (2009), DefenseReview has published a short “heads-up”-style article on the FailZero AR-15 Basic Kit, which is a bolt carrier group (BCG) and hammer upgrade kit with a proprietary and patented self-lubricitous/self-lubricating nickel-boron (Ni-B) coating that the company calls EXO Technology. In the video below, DefenseReview.com contributor ... Read More »